Design and Technical Manual

6. SYSTEM DESIGN
Limitation check
z
Diagram
Example
ft (m)
Limitation
ft (m)
Judge
Total pipe length Total
290
(89)
Less than 377 (115)
OK
Between outdoor unit and the farthest indoor unit a + b + c + l
180
(55)
Less than 230 (70)
OK
Between outdoor unit and branch boxes a + b + c + d + e
173
(53)
Less than 180 (55)
OK
Between branch box and indoor unit
Total f + i + l
117
(36)
Less than 197 (60)
OK
Each unit f, i, l
39
(12)
Between 10 to 49
(3 to 15)
OK
Between outdoor unit and the rst separation tube a
23
(7)
Greater than 16 (5)
OK
Calculation of additional charge refrigerant
z
Liquid pipe size
in. (mm)
1/4
(6.35)
3/8
(9.52)
Additional refrigerant
oz./ft. (g/m)
0.224
(21)
0.624
(58)
Liquid pipe length
ft (m)
117
(36)
173
(53)
Additional charge = (0.224 x 117) + (0.624 x 173) = 134.16 oz. = 8.39 lbs
[Additional charge = (21 x 36) + (58 x 53) = 3830 g = 3.83 kg]
- (06 - 25) -
SYSTEM DESIGN SYSTEM DESIGN